[talk-au] OpenStreetMap in Government

Ken Self kenself at optusnet.com.au
Thu May 16 05:07:24 UTC 2013


Verifiability is another topic altogether. My point was in relation to the
tags themselves.
My point is that information that is subjective, and targets a subset of
users, must be built into the tag and not the values. The tag must clearly
identify the population that it is relevant to. Whether that be "4WD
drivers" or "Daring 4WD drivers". But subjective information in the tag
values that is relevant to a subset of the population  is a bad idea because
the values are not necessarily mutually exclusive, as in your example.  
So rather than a tag such as "Suitability = Conventional Car; SUV; 4WD" the
tags should be along the lines of "Conventional_car_suitability=Y/N";
"SUV_suitability=Y/N"; "4WD_suitability=Y/N"
 
Both subjective and objective tags could be verifiable or unverifiable as
verifiability is a functon of the tag values rather than the tag.
 
For a subjective tag, verifiability is more difficult and would normally be
statistical e.g. "Recommended" or "Yes" could be defined as, say, "> 95% of
the target population successfully pass through". Assuming of course such
information is avaialble.
For objective tags, verifiability can sometimes be easy like "Width" and
others more statistical e.g. a "River" could be defined in terms of its long
term annual flow rate
 
 
-----Original Message-----
From: waldo000000 at gmail.com [mailto:waldo000000 at gmail.com] 
Sent: Thursday, 16 May 2013 8:01 AM
To: kenself at optusnet.com.au
Cc: David Bannon; OSM Australian Talk List
Subject: Re: [talk-au] OpenStreetMap in Government



On Tue, May 14, 2013 at 10:51 PM, Ken Self <kenself at optusnet.com.au> wrote:


Just jumping in here with some ideas. If you have an objective tag it is a
function of the track. But if you have a subjective tag then it is a
function of the user of the road/track.


A tag that is true for some and not true for others is not a good tag. e.g.
4WD_Suitability=Recommended may be true for some daring driver but not for
some other cautious driver. What I'm saying has been said many times before
-- please see http://wiki.openstreetmap.org/wiki/Verifiability. This
guideline is well-established and makes perfect sense to me.

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